U.S. patent number 11,181,742 [Application Number 16/567,691] was granted by the patent office on 2021-11-23 for display panel, and 3d display device and 3d head up display (hud) device using the display panel.
This patent grant is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. The grantee listed for this patent is SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Yoonsun Choi, Byong Min Kang, Jinho Lee, Dong Kyung Nam, Juyong Park.
United States Patent |
11,181,742 |
Kang , et al. |
November 23, 2021 |
Display panel, and 3D display device and 3D head up display (HUD)
device using the display panel
Abstract
Provided are a display panel and a three-dimensional (3D)
display device and a 3D head-up display (HUD) device using the
display panel. The display panel includes a plurality of pixels,
and a plurality of placement spaces provided between the plurality
of pixels, wherein the plurality of pixels are uniformly provided
in the display panel based on a pattern corresponding to the
plurality of placement spaces, and wherein a frequency
corresponding to a repetition interval of the pattern is outside of
a cognitive frequency band that is visible to a user.
Inventors: |
Kang; Byong Min (Yongin-si,
KR), Choi; Yoonsun (Yongin-si, KR), Nam;
Dong Kyung (Yongin-si, KR), Park; Juyong
(Seongnam-si, KR), Lee; Jinho (Suwon-si,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRONICS CO., LTD. |
Suwon-si |
N/A |
KR |
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Assignee: |
SAMSUNG ELECTRONICS CO., LTD.
(Suwon-si, KR)
|
Family
ID: |
68158962 |
Appl.
No.: |
16/567,691 |
Filed: |
September 11, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200110266 A1 |
Apr 9, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62741887 |
Oct 5, 2018 |
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Foreign Application Priority Data
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Jan 29, 2019 [KR] |
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10-2019-0011177 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N
13/305 (20180501); G02B 30/27 (20200101); G02B
30/29 (20200101); G02B 27/0172 (20130101); G02F
1/1339 (20130101); G02B 2027/014 (20130101) |
Current International
Class: |
G02F
1/1339 (20060101); G02B 27/01 (20060101); H04N
13/305 (20180101); G02B 30/27 (20200101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2016-139112 |
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Aug 2016 |
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JP |
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2016-142726 |
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Aug 2016 |
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JP |
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10-0538227 |
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Dec 2005 |
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KR |
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10-0662630 |
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Jan 2007 |
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KR |
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10-0725538 |
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Jun 2007 |
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KR |
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10-1441583 |
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Sep 2014 |
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KR |
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10-2016-0110876 |
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Sep 2016 |
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KR |
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10-1728821 |
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May 2017 |
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KR |
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Other References
Communication dated Mar. 10, 2020 issued by the European Patent
Office in counterpart European Patent Application No. 19201517.0.
cited by applicant .
Takaki, Y., et al., "Flat panel display with slanted pixel
arrangement for 16-view display", Proceedings of SPIE, vol. 7237,
Jan. 1, 2009, XP055035265, 8 pages. cited by applicant .
Chou et al., "Using Moire Chroma for DSC On-line Focus
Calibration", IS&T's 2003 PICS Conference, 2003, pp. 447-450, 4
pages total. cited by applicant .
Ko et al., "A Robust Method for Automatic Generation of Moire
Reference Phase from Noisy Image", vol. 10, No. 5, 2009, pp.
909-916, 8 pages total. cited by applicant.
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Primary Examiner: Lau; Edmond C
Attorney, Agent or Firm: Sughrue Mion, PLLC
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims benefit of U.S. Provisional Application No.
62/741,887 filed on Oct. 5, 2018 in the U.S. Patent and Trademark
Office, and claims the priority from Korean Patent Application No.
10-2019-0011177 filed on Jan. 29, 2019 in the Korean Intellectual
Property Office, the disclosures of which are incorporated herein
by reference in their entireties.
Claims
What is claimed is:
1. A display panel comprising: a plurality of pixels respectively
comprising a plurality of sub-pixels, the plurality of sub-pixels
included in each pixel of the plurality of pixels determining a
shape of each pixel; and a plurality of placement spaces provided
between the plurality of pixels, wherein the plurality of pixels
are uniformly provided in the display panel based on the plurality
of placement spaces, the plurality of pixels respectively having a
same shape in a horizontal direction and a vertical direction, and
forming a pattern repeated at an interval, and wherein, in a
frequency domain of an image obtained by the display panel, a
spatial frequency corresponding to the interval of the repeated
pattern formed by the plurality of pixels is outside of a cognitive
frequency band that is visible to a user, the cognitive frequency
band being less than 60 cycle/degree.
2. The display panel of claim 1, wherein the repeated pattern
comprises at least one pixel, and wherein a structure of subpixels
included in the at least one pixel is determined based on each of
the plurality of placement spaces in the display panel.
3. The display panel of claim 1, wherein a structure of subpixels
included in each of the plurality of pixels is determined based on
each of the plurality of placement spaces that comprise a
spacer.
4. The display panel of claim 3, wherein at least one of the
subpixels included in each of the plurality of pixels has a size
that is different from sizes of remaining subpixels included in
each of the plurality of pixels to correspond to each of the
plurality of placement spaces.
5. The display panel of claim 1, wherein a structure of subpixels
included in each of the plurality of pixels is determined based on
a combination of shapes, sizes, and gradients of the subpixels.
6. The display panel of claim 1, wherein the interval of the
repeated pattern comprises at least one of a first interval at
which the repeated pattern is repeated in the horizontal direction,
a second interval at which the repeated pattern is repeated in the
vertical direction, and a third interval at which the repeated
pattern is repeated in a direction corresponding to a combination
of the horizontal direction and the vertical direction.
7. The display panel of claim 1, wherein the plurality of pixels
comprise liquid crystals.
8. A third-dimensional (3D) display device comprising: a display
panel comprising a plurality of pixels and a plurality of placement
spaces provided between the plurality of pixels; and an optical
layer configured to control a direction of light incident from the
display panel, wherein the plurality of pixels are uniformly
provided in the display panel based on the plurality of placement
spaces, wherein the plurality of pixels respectively comprise a
plurality of sub-pixels, the plurality of sub-pixels included in
each pixel of the plurality of pixels determining a shape of each
pixel, wherein the plurality of pixels respectively have a same
shape in a horizontal direction and a vertical direction, and form
a pattern repeated at an interval, and wherein, in a frequency
domain of an image obtained by the display panel, a spatial
frequency corresponding to the interval of the repeated pattern
formed by the plurality of pixels is outside of a cognitive
frequency band that is visible to a user, the cognitive frequency
band being less than 60 cycle/degree.
9. The 3D display device of claim 8, wherein the repeated pattern
comprises at least one pixel, and wherein a structure of subpixels
included in the at least one pixel is determined based on each of
the plurality of placement spaces in the display panel.
10. The 3D display device of claim 8, wherein a structure of
subpixels included in each of the plurality of pixels is determined
based on each of the plurality of placement spaces that comprise a
spacer.
11. The 3D display device of claim 10, wherein at least one of the
subpixels included in each of the plurality of pixels has a size
that is different from sizes of remaining subpixels included in
each of the plurality of pixels to correspond to each of the
plurality of placement spaces.
12. The 3D display device of claim 8, wherein a structure of
subpixels included in each of the plurality of pixels is determined
based on a combination of shapes, sizes, and gradients of the
subpixels.
13. The 3D display device of claim 9, wherein the interval of the
repeated pattern comprises at least one of a first interval at
which the repeated pattern is repeated in the horizontal direction,
a second interval at which the repeated pattern is repeated in the
vertical direction, and a third interval at which the repeated
pattern is repeated in a direction corresponding to a combination
of the horizontal direction and the vertical direction.
14. A three-dimensional (3D) head-up display (HUD) device
comprising: a display panel comprising a plurality of pixels and a
plurality of placement spaces provided between the plurality of
pixels; an optical layer included in a windshield of a vehicle and
configured to control a direction of light incident from the
display panel; and at least one processor configured to generate a
panel image that is displayed on the display panel based on
positions of both eyes of a user to provide a 3D image to the user
through the optical layer, wherein the plurality of pixels are
uniformly provided in the display panel based on the plurality of
placement spaces, wherein the plurality of pixels respectively
comprise a plurality of sub-pixels, the plurality of sub-pixels
included in each pixel of the plurality of pixels determining a
shape of each pixel, wherein the plurality of pixels respectively
have a same shape in a horizontal direction and a vertical
direction, and form a pattern repeated at an interval, and wherein
a spatial frequency, in a frequency domain of the panel image
obtained by the display panel, corresponding to the interval of the
repeated pattern of the plurality of pixels is outside of a
cognitive frequency band that is visible to the user, the cognitive
frequency band being less than 60 cycle/degree.
15. The 3D HUD device of claim 14, wherein the repeated pattern
comprises at least one pixel, and wherein a structure of subpixels
included in the at least one pixel is determined based on each of
the plurality of placement spaces in the display panel.
16. The 3D HUD device of claim 14, wherein a structure of subpixels
included in each of the plurality of pixels is determined based on
each of the plurality of placement spaces that comprise a
spacer.
17. The 3D HUD device of claim 16, wherein at least a portion of
the subpixels included in each of the plurality of pixels has a
size that is different from sizes of remaining subpixels included
in each of the plurality of pixels to correspond to each of the
plurality of placement spaces.
18. The 3D HUD device of claim 14, wherein a structure of subpixels
included in each of the plurality of pixels is determined based on
a combination of shapes, sizes, and gradients of the subpixels.
19. The 3D HUD device of claim 14, wherein the interval of the
repeated pattern comprises at least one of a first interval at
which the repeated pattern is repeated in the horizontal direction,
a second interval at which the repeated pattern is repeated in the
vertical direction, and a third interval at which the repeated
pattern is repeated in a direction corresponding to a combination
of the horizontal direction and the vertical direction.
20. A display panel comprising: a plurality of pixels; a plurality
of subpixels included in each of the plurality of pixels; a
plurality of placement spaces provided between the plurality of
pixels, wherein the plurality of pixels are uniformly provided in
the display panel based on the plurality of placement spaces,
wherein the plurality of subpixels included in each pixel of the
plurality of pixels determine a shape of each pixel, wherein the
plurality of pixels respectively have a same shape in a horizontal
direction and a vertical direction, and form a pattern repeated at
an interval, and wherein, in a frequency domain of an image
obtained by the display panel, a spatial frequency corresponding to
the interval of the repeated pattern of the plurality of pixels is
outside of a cognitive frequency band that is visible to a user,
the cognitive frequency band being less than 60 cycle/degree.
21. The display panel of claim 20, wherein the plurality of
subpixels comprise at least a red sub-pixel, a green sub-pixel, and
a blue sub-pixel, and a size, a shape, and a gradient of the red
sub-pixel, the green sub-pixel, and the blue sub-pixel included in
each of the plurality of pixels are same, respectively.
22. The display panel of claim 21, wherein at least one of the red
sub-pixel, the green sub-pixel, and the blue sub-pixel included in
each of the plurality of pixels has a size that is different from
remaining subpixels included in each of the plurality of pixels
based on each of the placement spaces.
23. The display panel of claim 20, wherein each of the plurality of
placement spaces comprise a spacer.
Description
BACKGROUND
1. Field
Example embodiments of the present disclosure relate to a display
panel and a three-dimensional (3D) display device and a 3D head-up
display (HUD) device using the display panel.
2. Description of the Related Art
When two patterns that repeat at desired intervals overlap, a
pattern having a new repetition interval may be generated due to
interference between the patterns. Such the pattern is referred to
as moire. In general, a 3D display may be manufactured by
displacing a lens on a display panel. The moire may occur due to
pixels uniformly provided on the display panel and lens uniformly
provided thereon. The moire may cause a degradation in quality of a
3D image. In particular, a striped pattern by moire occurring when
the display panel is applied to a 3D HUD may interrupt driving.
SUMMARY
One or more example embodiments may address at least the above
problems and/or disadvantages and other disadvantages not described
above. Also, the example embodiments are not required to overcome
the disadvantages described above, and an example embodiment may
not overcome any of the problems described above.
According to an aspect of an example embodiment, there is provided
a display panel including a plurality of pixels, and a plurality of
placement spaces provided between the plurality of pixels, wherein
the plurality of pixels are uniformly provided in the display panel
based on a pattern corresponding to the plurality of placement
spaces, and wherein a frequency corresponding to a repetition
interval of the pattern is outside of a cognitive frequency band
that is visible to a user.
The pattern may include at least one pixel, and wherein a structure
of subpixels included in the at least one pixel may be determined
based on each of a plurality of placement spaces in the display
panel.
Each of the plurality of pixels may have a same shape.
The shape of each of the plurality of pixels may be determined
based on a pattern by a combination of a plurality of subpixels
included in each of the plurality of pixels, and each of the
plurality of pixels may have a same pattern in the display
panel.
A structure of subpixels included in the each of the plurality of
pixels may be determined based on each of the plurality of
placement spaces that may include a spacer.
At least one of the subpixels included in each of the plurality of
pixels may have a size that is different from sizes of remaining
subpixels included in each of the plurality of pixels to correspond
to each of the plurality of placement spaces.
A structure of subpixels included in each of the plurality of
pixels may be determined based on a combination of shapes, sizes,
and gradients of the subpixels.
The repetition interval of the pattern may include at least one of
a first interval at which the pattern is repeated in a horizontal
direction, a second interval at which the pattern is repeated in a
vertical direction, and a third interval at which the pattern is
repeated in a direction corresponding to a combination of the
horizontal direction and the vertical direction.
The plurality of pixels may include liquid crystals.
According to another aspect of an example embodiment, there is
provided a third-dimensional (3D) display device including a
display panel including a plurality of pixels and a plurality of
placement spaces provided between the plurality of pixels, and an
optical layer configured to control a direction of light incident
from the display panel, wherein the plurality of pixels are
uniformly provided in the display panel based on a pattern
corresponding to the plurality of placement spaces, and wherein a
frequency corresponding to a repetition interval of the pattern is
outside of a cognitive frequency band that is visible to a
user.
The pattern may include at least one pixel, and wherein a structure
of subpixels included in the at least one pixel is determined based
on each of a plurality of placement spaces in the display
panel.
Each of the plurality of pixels may have a same shape.
The shape of each of the plurality of pixels may be determined
based on a pattern by a combination of a plurality of subpixels
included in each of the plurality of pixels, and each of the
plurality of pixels has a same pattern in the display panel.
A structure of subpixels included in each of the plurality of
pixels may be determined based on each of the plurality of
placement spaces that may include a spacer.
At least one of the subpixels included in each of the plurality of
pixels may have a size that is different from sizes of remaining
subpixels included in each of the plurality of pixels to correspond
to each of the plurality of placement spaces.
A structure of subpixels included in each of the plurality of
pixels may be determined based on a combination of shapes, sizes,
and gradients of the subpixels.
The repetition interval of the pattern may include at least one of
a first interval at which the pattern is repeated in a horizontal
direction, a second interval at which the pattern is repeated in a
vertical direction, and a third interval at which the pattern is
repeated in a direction corresponding to a combination of the
horizontal direction and the vertical direction.
According to another aspect of an example embodiment, there is
provided a three-dimensional (3D) head-up display (HUD) device
including a display panel including a plurality of pixels and a
plurality of a placement spaces provided between the plurality of
pixels, and an optical layer included in a windshield of a vehicle
and configured to control a direction of light incident from the
display panel, and at least one processor configured to generate a
panel image that is displayed on the display panel based on
positions of both eyes of a user to provide a 3D image to the user
through the optical layer, wherein the plurality of pixels are
uniformly provided in the display panel based on a pattern
corresponding to the plurality of placement spaces, and a frequency
corresponding to a repetition interval of the pattern is outside of
a cognitive frequency band that is visible to the user.
The pattern may include at least one pixel, and wherein a structure
of subpixels included in the at least one pixel may be determined
based on each of a plurality of placement spaces in the display
panel.
A structure of subpixels included in each of the plurality of
pixels may be determined based on each of the plurality of
placement spaces that include a spacer.
At least a portion of the subpixels included in each of the
plurality of pixels may have a size that is different from sizes of
remaining subpixels included in each of the plurality of pixels to
correspond to each of the plurality of placement spaces.
A structure of subpixels included in each of the plurality of
pixels may be determined based on a combination of shapes, sizes,
and gradients of the subpixels.
The repetition interval of the pattern may include at least one of
a first interval at which the pattern is repeated in a horizontal
direction, a second interval at which the pattern is repeated in a
vertical direction, and a third interval at which the pattern is
repeated in a direction corresponding to a combination of the
horizontal direction and the vertical direction.
According to an aspect of an example embodiment, there is provided
a display panel including a plurality of pixels, a plurality of
subpixels included in each of the plurality of pixels, a plurality
placement spaces provided between the plurality of pixels, wherein
the plurality of pixels are uniformly provided in the display panel
based on a pattern of the plurality of subpixels corresponding to
the plurality of placement spaces, and wherein a frequency
corresponding to a repetition interval of the pattern is outside of
a cognitive frequency band that is visible to a user.
The plurality of subpixels may include at least a red sub-pixel, a
green sub-pixel, and a blue sub-pixel, and a size, a shape, and a
gradient of the red sub-pixel, the green sub-pixel, and the blue
sub-pixel included in each of the plurality of pixels are same,
respectively.
At least one of the red sub-pixel, the green sub-pixel, and the
blue sub-pixel included in each of the plurality of pixels may have
a size that is different from remaining subpixels included in each
of the plurality of pixels based on each of the placement
spaces.
Each of the plurality of placement spaces include a spacer.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and/or other aspects will be more apparent by describing
example embodiments with reference to the accompanying drawings, in
which:
FIGS. 1A, 1B, and 1C illustrate moire occurring on a display panel
in a pixel structure of a general dual domain display;
FIGS. 2A and 2B illustrate a pixel structure of a single domain
display panel and a frequency image corresponding to the pixel
structure according to an example embodiment;
FIGS. 3A, 3B, and 3C illustrate a display panel including pixels in
different patterns according to an example embodiment;
FIGS. 4A, 4B, and 4C illustrate a display panel including pixels in
the same pattern according to an example embodiment;
FIG. 5 is a flowchart illustrating a simulation method of a
three-dimensional (3D) display device according to an example
embodiment;
FIG. 6 illustrates a structure and an operation of a 3D head-up
device (HUD) device according to an example embodiment; and
FIGS. 7A, 7B, and 7C illustrate an occurrence reason of moire to be
solved according to an example embodiment.
DETAILED DESCRIPTION
Reference will now be made in detail to example embodiments,
examples of which are illustrated in the accompanying drawings,
wherein like reference numerals refer to the like elements
throughout. Example embodiments are described below in order to
explain the disclosure by referring to the figures.
The following structural or functional descriptions are example to
describe the example embodiments, and the scope of the example
embodiments is not limited to the descriptions provided in the
present specification. Various changes and modifications can be
made thereto by those of ordinary skill in the art.
Although terms of "first" or "second" are used to explain various
components, the components are not limited to the terms. These
terms may be used only to distinguish one component from another
component. For example, a "first" component may be referred to as a
"second" component, or similarly, and the "second" component may be
referred to as the "first" component within the scope of the right
according to the concept of the disclosure.
It will be understood that when a component is referred to as being
"connected to" another component, the component can be directly
connected or coupled to the other component or intervening
components may be present.
As used herein, the singular forms are intended to include the
plural forms as well, unless the context clearly indicates
otherwise. The terms "comprises" and/or "comprising," when used in
this specification, specify the presence of stated features,
integers, steps, operations, elements, components or a combination
thereof, but do not preclude the presence or addition of one or
more other features, integers, steps, operations, elements,
components, and/or groups thereof. Expressions such as "at least
one of," when preceding a list of elements, modify the entire list
of elements and do not modify the individual elements of the list.
For example, the expression, "at least one of a, b, and c," should
be understood as including only a, only b, only c, both a and b,
both a and c, both b and c, or all of a, b, and c.
Unless otherwise defined herein, all terms used herein including
technical or scientific terms have the same meanings as those
generally understood by one of ordinary skill in the art. Terms
defined in dictionaries generally used may be construed to have
meanings matching with contextual meanings in the related art and
are not to be construed as an ideal or excessively formal meaning
unless otherwise defined herein.
The following example embodiments may be applied to recognize a
user, to display a line in an augmented reality (AR) system, such
as a smart vehicle, or to generate visual information for assisting
steering of an autonomous driving vehicle. Also, the example
embodiments may be applied to track visual information and assist
safe and pleasant driving in a device that includes a smart system,
such as a head-up display (HUD) installed for driving assistance or
complete autonomous driving of a vehicle. The example embodiments
may be applied to, for example, a smartphone, a mobile device, a
navigation device, an autonomous driving vehicle, and a smart
vehicle.
FIG. 1 illustrate examples of moire occurring on a display panel in
a pixel structure of a general dual domain display. In detail, FIG.
1A illustrates an example of a pixel structure of a dual domain
display, FIG. 1B illustrates an example of a frequency image in the
pixel structure of FIG. 1A, and FIG. 1C illustrates an example of
moire occurring in response to manufacturing a 3D display in the
pixel structure of FIG. 1A.
Referring to FIG. 1A, the 3D display device may be manufactured by
overlapping lenses on a display panel that includes pixels. Here,
interference may occur due to the pixels and the lenses that are
uniformly placed on the display panel. That is, interference may
occur due to the lenses that are uniformly placed on a single
display panel on which the pixels are uniformly placed. When a
frequency of moire occurring due to the interference is in a low
frequency domain, a user may recognize the moire as a stripe. In
general, eyes of a human may not recognize a pattern with a
frequency of greater than or equal to 60 cycle/degree and may
recognize a pattern with a frequency of less than 60 cycle/degree.
The frequency of less than 60 cycle/degree may correspond to a
cognitive frequency band or a visibility circle. Referring to FIG.
1B, a portion indicated with a circle with a solid line represents
a boundary of a frequency of 60 cycle/degree and may be referred to
as a cognitive frequency boundary. Here, a frequency included in
the cognitive frequency boundary, that is, the frequency of less
than 60 cycle/degree may be a cognitive frequency of a moire
frequency. For a periodic interference pattern occurring due to
moire in a moire frequency may be recognized at eyes of the user as
moire as shown in FIG. 1C. Moire is a factor that degrades quality
of a 3D image and needs to be reduced or removed.
In general, a cause for moire may be more easily analyzed in a
frequency domain rather than in a space domain. Therefore, presence
or absence of moire may be verified from an image transformed to
the frequency domain. Also, although moire generally defines a
periodic pattern that is newly generated regardless of whether it
is visible to eyes of the user, a periodic pattern that is viewed
by eyes of the user may be moire for clarity of description. The
term periodic pattern may be a pattern that is repeated at a
desired interval.
In the dual domain display of FIG. 1A, odd rows of pixels are
tilted to the left and even rows of pixels are tilted to the right.
A pixel structure in which a pattern of pixels of odd rows and a
pattern of pixels of even rows are different may be a dual domain
structure. In the dual domain structure, a pixel pattern repetition
interval increases due to a difference between shapes of upper
pixels and lower pixels compared to a single domain structure, and
as a frequency is inversely proportional to the pattern repetition
interval, a frequency may decrease and be generated in a low
frequency domain accordingly. The overlap between a low frequency
and a lenticular lens may increase a moire occurrence
probability.
In one example, it is possible to remove moire from the cognitive
frequency band by changing a period of moire through a modification
in the pixel structure to decrease the pixel pattern repetition
interval. For example, the dual domain structure may be used to
enhance a viewing angle of a display. However, a device having a
relatively small viewing angle compared to a general display, such
as a head-up display (HUD) device, the dual domain structure for
enhancing the viewing angle may not be required. Accordingly, moire
may be removed from the cognitive frequency band by changing a
pixel structure of a dual domain with a pixel structure of a single
domain and thereby changing a period of moire.
FIG. 2 illustrates examples of a pixel structure of a single domain
display panel and a frequency image corresponding to the pixel
structure according to an example embodiment. FIG. 2A illustrates
an example of a 3D display device 250 configured to output light of
pixels 211 in a specific direction by placing an optical layer 230
on a display panel 210. FIG. 2B illustrates an example of a
frequency domain image when the optical layer 230 is attached on
the display panel 210.
For example, the display panel 210 may be a single domain display
panel on which even rows of pixels and odd rows of pixels are in
the same pattern. Each of the pixels 211 may include a plurality of
subpixels, for example, a red (R) subpixel 211-1, a green (G)
subpixel 211-2, and a blue (B) subpixel 211-3. In the single domain
display panel, all of the pixels 211 may have the same shape, the
same size, and the same gradient. Referring to FIG. 2B, when the 3D
display device 250 is manufactured using the single domain pixel
structure, moire does not occur in the cognitive frequency
band.
The optical layer 230 may be a lenticular lens or a barrier having
a periodical characteristic. For example, the optical layer 230 may
be a lenticular lens in a vertically elongated shape as a
semi-cylindrical lens. The optical layer 230 may control a
direction of light incident from the display panel 210.
In general, to maintain a panel thickness, a spacer (see FIG. 3A)
may be provided between the pixels 211. The spacer may be provided
between the pixels 211 to support a load by difference between an
internal pressure and an external pressure of the display panel
210. Shapes of some pixels 211 or some subpixels in the
corresponding pixel 211 may vary due to the spacer. Due to
different pixel shapes, a pixel pattern repetition interval may
increase, which may cause moire in the cognitive frequency band.
Hereinafter, moire occurring due to the spacer is described with
reference to FIGS. 3A, 3B, and 3C and a method of removing moire
occurring due to the pixel structure of FIG. 3 is described with
reference to FIGS. 4A, 4B, and 4C. As illustrated in FIG. 3A, the
spacer may be present within the display panel 210.
FIG. 3A illustrates examples of describing a display panel
including pixels in different patterns according to an example
embodiment. In detail, FIG. 3A illustrates an example of a display
panel 310 including spacers 311 and pixels 313. Shapes of the
pixels 313 included in the display 310 may vary due to the spacers
311. For example, due the spacer 311, shapes of R, G, B subpixels
included in the respective pixels 313 may differ from each other in
an odd row and an even row. For example, a size of an R subpixel
included in the pixel 313 of an odd row may be less than those of G
and B subpixels. Also, a size of an R subpixel included in the
pixel 313 of an even row may be less than those of B and G
subpixels. As described above with reference to FIG. 1, in response
to modifying a shape and/or a size of a pixel or a subpixel, a low
frequency may be generated in a frequency domain and the generated
low frequency may cause moire in a cognitive frequency band.
Referring to FIG. 3B, a 3D display device 330 includes the display
panel 310 and an optical layer 320. The display panel 310 may
include a plurality of pixels 313 and a plurality of spacers 311
configured to maintain a space for the plurality of pixels 313.
FIG. 3C illustrates an example of moire occurring in the cognitive
frequency band when the 3D display device 330 is manufactured using
the display panel 310 in the pixel structure of FIG. 3A. Such moire
occurring since a pixel shape varies due to the spacer 311 may be
solved through a pixel structure of FIGS. 4A and 4B.
FIGS. 4A and 4B illustrate a display panel including pixels in the
same pattern according to an example embodiment. For example, FIG.
4A illustrates an example of a display panel 410 including spacers
411 and pixels 413. Shapes of the pixels 413 included in the
display panel 410 may vary due to the spacers 411.
According to an example embodiment, the pixels 413 are uniformly
provided in the display panel 410 based on a pattern that is
determined based on the spacers 411. Here, the pattern may be
represented using shapes, sizes, and gradients of R, G, and B
subpixels included in an individual pixel. For example, each of the
pixels 413 may have the same shape, size, and gradient in an even
row and an odd row of the display panel 410 based on the determined
pattern. Here, the pattern may refer to a pattern in which R, G,
and B subpixels included in an individual pixel are arranged in
line, have the same gradient, and sizes of the R subpixel and the B
subpixel being less than that of the G subpixel.
The pixels 413 may have the same shape. For example, shapes of the
pixels 413 corresponding to a single pattern formed by R, G, and B
subpixels may be identical to each other. Also, the shapes of the
pixels 413 may be determined based on a pattern by a combination of
a plurality of subpixels included in an individual pixel and each
of the pixels 413 in the display panel 410 may have the same
pattern. For example, the shapes, sizes, and gradients of the R, G,
and B subpixels respectively included in each of the pixels 413 may
be identical.
As illustrated in FIGS. 4A and 4B, when the repetition interval of
a pattern is decreased, a frequency corresponding to a repetition
interval of a pattern increases and may not be included in a
cognitive frequency band of a user, for example, a cognitive
frequency boundary of 60 cycle/degree. The repetition interval of
the pattern may include at least one of a first interval at which
the pattern is repeated in a horizontal direction, a second
interval at which the pattern is repeated in a vertical direction,
and a third interval at which the pattern is repeated in a
direction corresponding to a combination of the horizontal
direction and the vertical direction.
The pattern may include at least one pixel 413 and a structure of
subpixels included in the pixel 413 may be determined based on a
spacer placement space in the display panel 410. In particular, a
structure of the subpixels included in the pattern may be
determined based on the spacer placement space that is maintained
regardless of whether the spacer 411 is actually provided. For
example, the structure of the subpixels 413 included in the pattern
may be in a structure where a spacer placement space is empty at an
upper end and/or lower end of an R subpixel and at an upper end
and/or lower end of a B subpixel in which the spacer 411 may be
placed, regardless of whether the spacer 411 is actually
placed.
That is, at least one of the subpixels included in a pixel may have
a size different from that of remaining pixels included in the
pixel to secure the placement space. For example, a pixel may
include an R subpixel with a first size, a G subpixel with a second
size greater than the first size, and a B subpixel with the first
size. According to an example embodiment, the pixel may include the
R subpixel with the first size, the G subpixel with the second size
less than the first size, and the B subpixel with a third size less
than the first size and greater than the second size.
For example, the placement space of the spacer 411 may be prepared
to be adjacent to the R subpixel and the B subpixel. In addition,
the structure of subpixels included in the pattern may be
determined based on various combinations of shapes, sizes, and
gradients of subpixels.
According to an example embodiment, a pixel repetition interval may
be reduced by adjusting a size of a subpixel in an area in which
the spacer 411 is not actually placed. As described above, as the
pixel repetition interval decreases the frequency increases, and
thus moire may be removed from the cognitive frequency band.
FIG. 4A illustrates an example in which the pixels 413 of the
display panel 410 are in the same shape. FIG. 3A illustrates an
example in which the pixels 313 of the display panel 310 are in
different shapes. Here, an additional frequency component may be
generated or present in addition to a pixel repetition interval
based on an interval at which a new pattern is repeated due to the
pixels in the different shape. Here, the new pattern may be, for
example, a pattern configured based on a unit of n.times.m pixels
where n and m denote positive integers and at least one of n and m
is 2 or more. For example, when a lenticular lens is overlapped on
a pixel structure having a new pattern, a new interference
frequency may be generated in a frequency component due to the
lenticular lens. Overlapping of the lenticular lens may represent a
convolution effect in a frequency image. Accordingly, the simpler a
frequency by a pixel repetition pattern becomes, the less an
interference frequency is generated, which may decrease a
probability that the interference frequency is included in the
cognitive frequency band.
Referring to FIG. 4B, a 3D display device 430 includes the display
panel 410 and an optical layer 420. The display panel 410 may
include a plurality of pixels 413 and a plurality of spacers 411
configured to maintain a space for the plurality of pixels 413.
FIG. 4C illustrates an example of a frequency domain of the 3D
display device 430 in the pixel structure of FIG. 4A. Referring to
FIG. 4C, a moire frequency is absent in the cognitive frequency
band.
FIG. 5 is a flowchart illustrating an example of a simulation
method of a 3D display device according to an example embodiment. A
process of performing a simulation to prevent or reduce occurrence
of moire without directly attaching a lens using a simulation
apparatus according to an example embodiment is described with
reference to FIG. 5. Referring to FIG. 5, in operation 510, the
simulation apparatus may generate a panel image to provide a 3D
image to which an optical characteristic is applied. Here, the 3D
image may include a left image and a right image as images that are
provided to both eyes of a user, for example, a viewer. The 3D
image may be an input image, for example, augmented reality (AR)
content. The panel image may be an image represented on a display
panel of the 3D display device and may be generated based on
positions of eyes of the user and direction information of light to
provide a 3D image to the user. For the simulation operation of
FIG. 5, the simulation apparatus may generate a white image in
which all of the pixels are ON as the panel image.
In operation 520, the simulation apparatus may change an optical
characteristic, for example, a pitch and/or angle, of a lens of the
3D display device. In operation 530, the simulation apparatus may
generate an overlapping image by applying the optical
characteristic changed in operation 520. The overlapping image may
be an image that is formed at both eyes of the user. For example,
when the 3D image is provided from the 3D display device, the
simulation apparatus may capture the overlapping image.
In operation 540, the simulation apparatus may transform the
overlapping image to an image of a frequency domain. In operation
550, the simulation apparatus may determine whether a moire
frequency included in the image of the frequency domain is present
within a cognitive frequency band. For example, when the moire
frequency included in the frequency domain image is less than a
cognitive frequency boundary in operation 550, the simulation
apparatus may again change the optical characteristic of the lens
of the display panel in operation 520.
On the contrary, when moire within the cognitive frequency band is
determined to be absent in the image of the frequency domain in
operation 550, the simulation apparatus may determine the
corresponding optical characteristic as the optical characteristic
of the lens in operation 560.
FIG. 6 illustrates an example of describing a structure and an
operation of a 3D HUD device according to an example embodiment.
Referring to FIG. 6, a 3D HUD device 600 may include a display
panel 610, a picture generation unit (PGU) 630 including a
backlight unit (BLU) 620, and an optical layer 640.
The display panel 610 includes a plurality of pixels and a
plurality of spacers configured to maintain a space for the
plurality of spacers. The pixels are uniformly provided in the
display panel 610 based on a pattern that is determined based on
the plurality of spacers, and a frequency corresponding to a
repetition interval of the pattern is not included in a cognitive
frequency band of a user. The description made above with respect
to the display panel 410 of FIG. 4 may be applicable to the display
panel 610.
The BLU 620 may uniformly emit light at the rear of the display
panel 610.
To provide a 3D image 650 to the user through the optical layer
640, the PGU 630 generates a panel image 660 displayed on the
display panel 610 based on positions of both eyes of the user. The
PGU 630 may include at least one processor.
FIGS. 7A, 7B, and 7C illustrate related examples of describing an
occurrence reason of moire to be solved according to an example
embodiment. FIG. 7A illustrates an example of representing an image
displayed on a display panel in a space domain and FIG. 7C
illustrates an example of transforming the space domain of the
image of FIG. 7A to a frequency domain. The overlapping of two
images may be convolution of two frequency transformed images in
the frequency domain.
An image of FIG. 7A may have a .+-.f1 vector in the frequency
domain, and an image of FIG. 7B may have a .+-.f2 vector in the
frequency domain. Here, the .+-.f1 vector and the .+-.f2 vector may
represent periodic patterns of the respective images. The periodic
pattern may be represented as moire in the mage.
An image of FIG. 7C may further have an f1+f2 vector, a -f1-f2
vector, an f1-f2 vector, and an f2-f1 vector, in addition to the
.+-.f1 vector and the .+-.f2 vector as convolution of the two
vectors .+-.f1 and .+-.f2 in the frequency domain. The f1+f2 vector
and the -f1-f2 vector may have a high frequency compared to an
original image, and the f1-f2 vector and the f2-f1 vector may have
a low frequency compared to the original image. Here, when the
f1-f2 vector and the f2-f1 vector are present in a cognitive
frequency band, a stripped pattern may appear in a direction
corresponding to the f1-f2 vector and the f2-f1 vector. A frequency
vector may have a direction and a magnitude. A vector direction
represents a direction of the striped pattern and is well visible
at eyes of a person as a frequency of moire becomes lower. Also,
the frequency vector may have an impulse indicating a brightness
level of the image.
The example embodiments described herein may be implemented using
hardware components, software components, and/or a combination
thereof. For example, the apparatuses, methods, processing device,
and components described herein may be implemented using one or
more general-purpose or special purpose computers, such as, for
example, a processor, a controller and an arithmetic logic unit
(ALU), a digital signal processor, a microcomputer, a field
programmable gate array (FPGA), a programmable logic unit (PLU), a
microprocessor, or any other device capable of responding to and
executing instructions in a defined manner. The processing device
may run an operating system (OS) and one or more software
applications that run on the OS. The processing device also may
access, store, manipulate, process, and create data in response to
execution of the software. For purpose of simplicity, the
description of a processing device is used as singular, however,
one skilled in the art will be appreciated that a processing device
may include multiple processing elements and/or multiple types of
processing elements. For example, a processing device may include
multiple processors or a processor and a controller. In addition,
different processing configurations are possible, such as parallel
processors.
While example embodiments have been described, it will be
understood by those of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope as defined by the following claims.
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